• Programmable Output Voltage to 36V
• Low Dynamic Output Impedance 0.2Ω
• Sink Current Capability of 0.1 mA to 100 mA
• Equivalent Full-Range Temperature Coefficient of 50 ppm/oC
• Temperature Compensated for Operation over Full Rated
Operating Temperature Range
• Low Output Noise Voltage
• Fast Turn on Response
DESCRIPTION
The TL431 is a three-terminal adjustable regulator series with a guaranteed thermal stability over
applicable temperature ranges. The output voltage may be set to any value between Vref
(approximately 2.5 volts) and 36 volts with two external resistors. These devices have a typical
dynamic output impedance of 0.2Ω. Active output circuitry provides a very sharp turn-on
characteristic, making these devices excellent replacement for zener diodes in many applications.
The TL431 is characterized for operation from 0oC to +70oC.
SYMBOL FUNCTIONAL BLOCK DIAGRAM
SCHEMATIC DIAGRAM
Reference
(R ) Cathode
(K )
Anode (A)
2.5V
ref
+
-
Reference
(R )
Cathode
(K )
Anode
(A )
Wing Shing Computer Components Co., (H.K.)Ltd. Tel:(852)2341 9276 Fax:(852)2797 8153
Homepage: http://www.wingshing.com E-mail: wsccltd@hkstar.com
SOT—
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Adjustable Precision Shunt Regulator
Pin Configuration
4-1
TL431
TO-92
REF
ANODE
CATHODE
REF
ANODE
CATHODE
TL431CLP
TL431LT1
TL431CPK
1. REF
2. CATHODE
3. ANODE
C
A
R
ABSOLUTE MAXIMUM RATINGS
(Operating temperature range applies unless otherwise specified)
Characteristic Symbol Value Unit
Cathode Voltage VKA 37 V
Cathode Current Range (Continuous) IK -100 ~ +150 mA
Reference Input Current Range IREF 0.05 ~ +10 mA
Operating Temperature Range Ta 0 ~ +70 oC
Storage Temperature Range Tstg -65 ~ +150 oC
RECOMMENDED OPERATING CONDITIONS
Characteristic Symbol Test Condition Min Typ Max Unit
Cathode Voltage VKA V
REF 36 V
Cathode Current IK 1.0 100 mA
ELECTRICAL CHARACTERISTICS
(Ta = 25oC, unless otherwise specified)
Characteristic Symbol Test Condition Min Typ Max Unit
Reference Input Voltage VREF V
KA = VREF, IK = 10mA 2.44 2.495 2.55 V
Deviation of Reference
Input Voltage Over-
Temperature (Note 1)
VREF(dev) V
KA = VREF, IK = 10mA
Tmin ≤ Ta ≤ Tmax
4 17 mV
Ratio of Change in
Reference Input Voltage
to the Change in
∆
∆V
VREF
KA
IK = 10mA ∆VKA = 10V-VREF -1.4 -2.7
mV/V
Cathode Voltage ∆KKA = 36V-10V -1.0 -2.0
Reference Input Current IREF IK = 10mA, R1 = 10KΩ, R2 = ∞ 2,0 4 µA
Deviation of Reference
Input Current Over Full
Temperature Range
IREF(dev) IK = 10mA, R1 = 10KΩ, R2 = ∞
Ta = Full Range
0.4 1.2
µA
Minimum Cathode
Current for Regulation IK(min) V
KA = VREF 0.4 1.0 mA
Off-State Cathode
Current IK(off) V
KA = 36V, VREF = 0 0.1 1.0 µA
Dynamic Impedance
(Note2) ZKA V
KA = VREF, IK = 10mA to
100mA
f ≤ 1.0KHz
0.2 0.5 Ω
WS
TL431
4-2
Note: 1. T he deviation parameters VREF(dev) and IREF(dev) are defined as the differences between the maximum and minimum
values obtained over the rated temperature range.
VREF(dev) = VREF(max) - VREF(min)
The equivalent full-range temperature coefficient of the reference input voltage, αVREF is defined as:
αVREF
()
ppm
C
° =
( )
V
V@C
Ta
REF(dev)
REF °×106
∆
where ∆Ta is the rated operating fr ee-air temperature range of the device.
αVREF can be positive or negative depending on whether minimum
VREF or maximum VREF respectively, occurs at the lower temperature.
2. The dynamic impedance is defined as:
ZKA = ∆
∆
V
I
KA
K
When the device is operated with two external resistors (see Figure 2), the total dynamic impedance of the circuit is
given by:
Z' = ∆
∆
V
I = ZKA (1+ R
R
1
2)
TEST CIRCUITS
Fig.1. Test Circuit for VKA = VREF Fig.2. Test Circuit for VKA ≥
≥≥
≥ VREF
Fig.3. Test Circuit for Ioff
WS
TL431
4-3
PAD LAYOUT
PAD LOCATION
Unit: µm
Pad No. Pad Name Description X Y
1 R Reference 235 400
2 K Cathode -505 343.5
3 K Cathode -497.5 -346
4 A Anode -177.5 -341.5
Physical Characteristics
Wafers 4 inch 460 ± 40 µm (thickness)
Size 1.35 × 0.99 mm
Scribe width 90 µm
Wafer’s Backsid e Ti – Ni – Ag: Ti - 0.1 ± 0.02 µm
Ni - 0.5 ± 0.1 µm
Ag - 0.6 ± 0.1 µm
Passivation PSG
TL431 PAD DI AGRAM
Chi p size: 1345 x 990
Pad size :
Unit : m
µ
(0 ,0 )
2
34 1
WS
TL431
4-4